使用数据集和数据适配器对数据库增删改查

using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Data.SqlClient;//导入命名空间

public partial class chap09_DataAccessDemo : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {

    }
    protected void btnQuery_Click(object sender, EventArgs e)
    {
        SqlDataAdapter da = new SqlDataAdapter();

        //创建连接对象
        SqlConnection conn = new SqlConnection();
        conn.ConnectionString = "Data Source=LIYONGPING;Initial Catalog=BookShop;User ID=sa;Password=2008aozheng@))^";
        //创建命令对象
        SqlCommand selectCmd = new SqlCommand();
        selectCmd.CommandText = "select * from Books";
        selectCmd.Connection = conn;

        //设置数据适配器的SelectCommand属性
        da.SelectCommand = selectCmd;

        //创建数据集对象
        DataSet data = new DataSet();
        //使用数据适配器填充数据集
        da.Fill(data, "Books");
       
        //将数据显示在页面的GridView控件上
        GridView1.DataSource = data.Tables["Books"];
        GridView1.DataBind();
    }
    protected void btnAdd_Click(object sender, EventArgs e)
    {
        //第一步验证数据……
        //
        SqlDataAdapter da = new SqlDataAdapter();
        //创建连接对象
        SqlConnection conn = new SqlConnection();
        conn.ConnectionString = "Data Source=LIYONGPING;Initial Catalog=BookShop;User ID=sa;Password=2008aozheng@))^";
        //创建查询命令对象
        SqlCommand selectCmd = new SqlCommand();
        selectCmd.CommandText = "select * from Books";
        selectCmd.Connection = conn;

        //创建添加数据的命令对象
        SqlCommand insertCmd = new SqlCommand();
        insertCmd.CommandText = "insert into Books values(@BookName,@Author,@Publisher,@UnitPrice,@Discount,@BookImageFileName)";
        insertCmd.Connection = conn;
        //向插入命令添加参数
        /*
        SqlParameter bookNameParam = new SqlParameter("@BookName", SqlDbType.NVarChar, 50);
        bookNameParam.SourceColumn = "BookName";
        insertCmd.Parameters.Add(bookNameParam);
        */
        insertCmd.Parameters.Add("@BookName",SqlDbType.NVarChar, 50, "BookName");
        insertCmd.Parameters.Add("@Author", SqlDbType.NVarChar, 50, "Author");
        insertCmd.Parameters.Add("@Publisher", SqlDbType.NVarChar,50, "Publisher");
        insertCmd.Parameters.Add("@UnitPrice", SqlDbType.Money, 8, "UnitPrice");
        insertCmd.Parameters.Add("@Discount", SqlDbType.NVarChar, 8, "Discount");
        insertCmd.Parameters.Add("@BookImageFileName", SqlDbType.NVarChar, 50, "BookImageFileName");
        //设置数据适配器的SelectCommand属性/InsertCommand
        da.SelectCommand = selectCmd;
        da.InsertCommand = insertCmd;
        //创建数据集对象
        DataSet data = new DataSet();
        //使用数据适配器填充数据适配器
        da.Fill(data, "Books");

        //向DataSet的“Books”表中添加一条记录
        DataRow drNew=data.Tables["Books"].NewRow();
        //设置新添加行的值
        drNew["BookName"] = txtBookName.Text;
        drNew["Author"] = txtAuthor.Text;
        drNew[3] = txtPublishName.Text;
        drNew[4] = txtPrice.Text;
        drNew[5] = txtDiscount.Text;
        drNew[6] = txtFileName.Text;
        //向表中添加行
        data.Tables["Books"].Rows.Add(drNew);
        //将数据通过数据适配器更新到数据库中
        da.Update(data, "Books");
    }
    protected void btnEdit_Click(object sender, EventArgs e)
    {
        //第一步验证数据……
        //
        SqlDataAdapter da = new SqlDataAdapter();
        //创建连接对象
        SqlConnection conn = new SqlConnection();
        conn.ConnectionString = "Data Source=LIYONGPING;Initial Catalog=BookShop;User ID=sa;Password=2008aozheng@))^";
        //创建查询命令对象
        SqlCommand selectCmd = new SqlCommand();
        selectCmd.CommandText = "select * from Books";
        selectCmd.Connection = conn;

        //创建修改数据的命令对象
        SqlCommand editCmd = new SqlCommand();
        editCmd.CommandText = "update Books set Discount=@Discount where BookID=@BookID";
        editCmd.Connection = conn;
        //向修改数据命令添加参数
       
        editCmd.Parameters.Add("@BookID", SqlDbType.Int, 4, "BookID");
        editCmd.Parameters.Add("@Discount", SqlDbType.Float, 8, "Discount");
        //editCmd.Parameters["@BookID"].SourceVersion = DataRowVersion.Original;
        //设置数据适配器的SelectCommand属性/UpdateCommand属性
        da.SelectCommand = selectCmd;
        da.UpdateCommand = editCmd;
        //创建数据集对象
        DataSet data = new DataSet();
        //使用数据适配器填充数据适配器
        da.Fill(data, "Books");
       
        //查找需要更改的行
       
        DataRow[] drSelect=data.Tables["Books"].Select("BookID="+txtBookIDForEdit.Text.Trim());
        DataRow editDr;
        if (drSelect.Length > 0)
        {
            editDr = drSelect[0];
        }
        else
        {
            return;
        }
      
      
        /*
        data.Tables["Books"].PrimaryKey = new DataColumn[] { data.Tables["Books"].Columns["BookID"] };
        DataRow editDr=data.Tables["Books"].Rows.Find(int.Parse(txtBookIDForEdit.Text));
        if (editDr == null)
            return;
         */
        /*
        int nBookID = int.Parse(txtBookIDForEdit.Text);

        DataRow editDr = null;
        foreach (DataRow dr in data.Tables["Books"].Rows)
        {
            if (int.Parse(dr["BookID"].ToString()) == nBookID)
            {
                editDr = dr;
                break;
            }
        }
        */
        editDr["Discount"] = txtNewDiscount.Text;

        //将数据通过数据适配器更新到数据库中
        da.Update(data, "Books");
    }
    protected void btnDel_Click(object sender, EventArgs e)
    {
        //第一步验证数据……
        //
        SqlDataAdapter da = new SqlDataAdapter();
        //创建连接对象
        SqlConnection conn = new SqlConnection();
        conn.ConnectionString = "Data Source=LIYONGPING;Initial Catalog=BookShop;User ID=sa;Password=2008aozheng@))^";
        //创建查询命令对象
        SqlCommand selectCmd = new SqlCommand();
        selectCmd.CommandText = "select * from Books";
        selectCmd.Connection = conn;

        //创建删除数据的命令对象
        SqlCommand delCmd = new SqlCommand();
        delCmd.CommandText = "delete Books where BookID=@BookID";
        delCmd.Connection = conn;
        //向删除数据命令添加参数

        delCmd.Parameters.Add("@BookID", SqlDbType.Int, 4, "BookID");
      
        //editCmd.Parameters["@BookID"].SourceVersion = DataRowVersion.Original;
        //设置数据适配器的SelectCommand属性/DeleteCommand属性
        da.SelectCommand = selectCmd;
        da.DeleteCommand = delCmd;
        //创建数据集对象
        DataSet data = new DataSet();
        //使用数据适配器填充数据适配器
        da.Fill(data, "Books");

        int nBookID = int.Parse(txtBookIDForDel.Text);
        DataRow delDr=null;
        foreach (DataRow dr in data.Tables["Books"].Rows)
        {
            if (int.Parse(dr["BookID"].ToString()) == nBookID)
            {
                delDr = dr;
                break;
            }
        }
        if (delDr != null)
        {
            delDr.Delete();//从数据集中删除改行

            //将数据通过数据适配器更新到数据库中
            da.Update(data, "Books");
        }
    }
}